JP2023067438A - Method for manufacturing non-pneumatic tire - Google Patents

Abstract

To provide a method for manufacturing a non-pneumatic tire capable of ensuring adhesion between a support structure and tread rubber without using the support structure containing resin having a specific chemical structure or specific physical properties.SOLUTION: In a method for manufacturing a non-pneumatic tire, the non-pneumatic tire includes: a support structure 10 containing resin; and a tread located outside the support structure 10 in a tire radial direction X and extending along a tire circumferential direction. The method for manufacturing the non-pneumatic tire includes the steps of: surface-modifying an outer surface of the support structure 10 in the tire radial direction X so that a wet tension is 40 mN/m or more and 60 mN/m or less; applying a vulcanizing adhesive 2 to a surface modified surface of the support structure 10; and vulcanizing and bonding the support structure 10 coated with the vulcanizing adhesive 2 and a tread rubber composition 3.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for manufacturing non-pneumatic tires.

Conventionally, a non-pneumatic tire is known that includes a support structure that supports a load from a vehicle, and a tread that is located radially outside the support structure and extends along the tire circumferential direction. .

In a non-pneumatic tire, if the tread peels off from the support structure, the running of the vehicle will be hindered. Therefore, it is desired to secure the adhesive force between the support structure and the tread.

Therefore, in Patent Document 1, it is described that a support structure is produced by curing a polyurethane composition containing an isocyanate-terminated prepolymer having a double bond in the main chain, an organic sulfide, and dimethylthiotoluenediamine. It is

Further, Patent Document 2 describes that the storage elastic modulus at 150° C. of the resin contained in the connecting structure portion connecting the inner annular portion and the outer annular portion of the support structure is set to 8 MPa or more.

Japanese Patent No. 5175587 Japanese Patent Application Laid-Open No. 2019-218002

However, in Patent Documents 1 and 2, it is necessary to use a support structure containing a resin having a specific chemical structure or specific physical properties.

The present invention provides a method for manufacturing a non-pneumatic tire capable of ensuring adhesion between a support structure and a tread without using a support structure containing a resin having a specific chemical structure or specific physical properties. intended to provide

One aspect of the present invention provides a non-pneumatic tire comprising a support structure containing a resin, and a tread located outside the support structure in the tire radial direction and extending along the tire circumferential direction. A method for manufacturing, comprising a step of surface-modifying the outer surface of the support structure in the tire radial direction so that the wet tension is 40 mN / m or more and 60 mN / m or less, and the surface of the support structure It includes a step of applying a vulcanizing adhesive to the modified surface, and a step of vulcanizing bonding the support structure to which the vulcanizing adhesive is applied and the tread rubber composition.

The surface modification may be surface modification by corona treatment or plasma treatment.

The resin may be a urethane resin, and the vulcanization adhesive may contain a halogenated polymer.

According to the present invention, there is provided a non-pneumatic tire capable of ensuring adhesion between a support structure and a tread without using a support structure containing a resin having a specific chemical structure or specific physical properties. A manufacturing method can be provided.

It is a side view which shows the non-pneumatic tire of this embodiment. FIG. 2 is a cross-sectional view showing an example of a method of manufacturing the non-pneumatic tire of FIG. 1; FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1; FIG. 4 is a partial perspective view of a non-pneumatic tire viewed obliquely from the portion shown in FIG. 3;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

A method for manufacturing a non-pneumatic tire according to the present embodiment includes a support structure containing a resin, and a tread located outside the support structure in the tire radial direction and extending along the tire circumferential direction. A method for manufacturing a non-pneumatic tire.

FIG. 1 shows a non-pneumatic tire of this embodiment. A non-pneumatic tire 1 comprises a support structure 10 and a tread 50 . Here, the support structure 10 contains resin and supports the load from the vehicle. Further, the tread 50 is located outside the support structure 10 in the tire radial direction X and extends along the tire circumferential direction C. As shown in FIG. Details of the structure of the non-pneumatic tire 1 will be described later.

FIG. 2 shows an example of a method for manufacturing the non-pneumatic tire 1. As shown in FIG. When manufacturing the non-pneumatic tire 1, first, the outer surface of the support structure 10 in the tire radial direction X is surface-modified. At this time, the wet tension of the surface-modified surface of the support structure 10 is 40 mN/m or more and 60 mN/m or less, preferably 50 mN/m or more and 55 mN/m or less. When the surface-modified surface of the support structure 10 has a wet tension of 40 mN/m or more and 60 mN/m or less, the adhesion between the support structure 10 and the tread 50 is improved.

The surface modification method is not particularly limited, but includes a method of surface modification by corona treatment, a method of surface modification by plasma treatment, and the like.

When the outer surface of the support structure 10 in the tire radial direction X is surface-modified by corona treatment or plasma treatment, for example, the support structure 10 is rotated around the axis O of the non-pneumatic tire 1 as a rotation axis. Discharge while

A vulcanizing adhesive 2 is then applied to the surface-modified surface of the support structure 10 . At this time, the vulcanization adhesive 2 is preferably applied within 24 hours, more preferably within 12 hours, after the support structure 10 is surface-modified. If the vulcanizing adhesive 2 is applied within 24 hours after surface modification of the support structure 10, the adhesion between the support structure 10 and the tread 50 is improved.

The coating film thickness of the vulcanizing adhesive 2 is preferably 1.0 μm or more and 23.0 μm or less, more preferably 5.0 μm or more and 20.0 μm or less. When the coating film thickness of the vulcanizing adhesive 2 is 1.0 μm or more and 23.0 μm or less, the adhesion between the support structure 10 and the tread 50 is improved.

In addition, the vulcanization adhesive 2 may be dried if necessary. The drying conditions are not particularly limited, but are, for example, a temperature of 50° C. or higher and 80° C. or lower for 5 minutes or longer and 10 minutes or shorter.

Next, after the tread rubber composition 3 is adhered to the surface of the support structure 10 to which the vulcanization adhesive 2 has been applied, the support structure 10 and the support structure 10 are formed by applying heat and pressure using a vulcanization apparatus. , and the tread rubber composition 3 are vulcanized and bonded.

The pressure applied when vulcanizing and bonding the support structure 10 and the tread rubber composition 3 is preferably 0.6 MPa or more, more preferably 0.8 MPa or more. When the pressure is 0.6 MPa or more when the support structure 10 and the tread rubber composition 3 are vulcanized and bonded, the adhesion between the support structure 10 and the tread 50 is improved.

Here, since the wetting tension of the outer surface of the support structure 10 in the tire radial direction X is 40 mN/m or more and 60 mN/m or less, the compatibility between the support structure 10 and the vulcanization adhesive 2 is good. As a result, the adhesion between the support structure 10 and the tread 50 can be ensured without using a support structure containing a resin having a specific chemical structure or specific physical properties. On the other hand, when the wet tension of the outer surface of the support structure 10 in the tire radial direction X is less than 40 mN/m or exceeds 60 mN/m, the support structure 10 and the vulcanization adhesive 2 This results in poor compatibility between the substrates and, as a result, the need to use support structures comprising resins with specific chemical structures or specific physical properties.

The material forming the outer surface of the support structure 10 in the tire radial direction X is not particularly limited, but examples thereof include thermoplastic elastomers, crosslinked rubbers, and other resins.

Here, when the resin constituting the outer surface in the tire radial direction X of the support structure 10 is a urethane resin, the vulcanizing adhesive 2 can be a vulcanizing adhesive containing a halogenated polymer. At this time, the vulcanization adhesive 2 may further contain a metal oxide (acid acceptor) as needed.

A known urethane resin used for the support structure 10 can be used as the urethane resin. As the halogenated polymer and metal oxide (acid acceptor), known halogenated polymers and metal oxides (acid acceptors) used for vulcanizing adhesives can be used, respectively.

Although not particularly limited, the tread rubber composition 3 contains, for example, natural rubber and carbon black, and may further contain sulfur, silica, and the like. Here, the tread rubber composition 3 may contain synthetic rubber such as polyisoprene rubber and styrene-butadiene rubber together with or instead of natural rubber.

The tread rubber composition 3 may be either an unvulcanized rubber composition or a vulcanized rubber composition.

The vulcanization temperature is not particularly limited, but is, for example, 140° C. or higher and 180° C. or lower.

The arithmetic mean roughness Ra of the outer surface in the tire radial direction X of the support structure 10 is preferably 2.0 μm or more and 18.0 μm or less, and more preferably 5.0 μm or more and 18.0 μm or less. When the arithmetic mean roughness Ra of the outer surface of the support structure 10 in the tire radial direction X is 2.0 μm or more and 18.0 μm or less, the adhesion between the support structure 10 and the tread 50 is improved.

A method for adjusting the surface roughness of the outer surface of the support structure 10 in the tire radial direction X is not particularly limited, but examples thereof include buffing. In this case, the buffed side of the support structure 10 is preferably degreased and washed.

The details of the structure of the non-pneumatic tire 1 (see FIG. 1) will be described below. FIG. 1 is a side view of the non-pneumatic tire 1 of the present embodiment viewed from a direction parallel to the tire rotation axis (tire meridian), that is, from a direction along the front and back direction of the paper in FIG. The non-pneumatic tire 1 shown in FIG. 1 is in an unloaded state. FIG. 3 is a cross-sectional view taken along line II-II of FIG. FIG. 4 is a partial perspective view of the non-pneumatic tire 1, obliquely viewing the portion shown in FIG.

1 and 4, arrow C indicates the tire circumferential direction. 1, 3 and 4, the arrow X indicates the tire radial direction. 3 and 4, arrow Y indicates the tire width direction. The tire width direction Y in FIG. 1 is the front-back direction of the paper surface. Symbol E in FIG. 3 is the tire equatorial plane. The tire circumferential direction C in FIG. 3 is the front-back direction of the paper surface.

The tire circumferential direction C is the direction around the tire rotation axis and the same direction as the direction in which the non-pneumatic tire 1 rotates. The tire radial direction X is a direction perpendicular to the tire rotation axis. The tire width direction Y is a direction parallel to the tire rotation axis. 3 and 4, one side in the tire width direction Y is indicated as Y1, and the other side in the tire width direction Y is indicated as Y2. The tire equatorial plane E shown in FIG. 3 is a plane orthogonal to the tire rotation axis and located at the center in the tire width direction Y. As shown in FIG.

The non-pneumatic tire 1 of this embodiment comprises an inner annular portion 20 , an outer annular portion 30 , a support structure 10 having a plurality of spokes 40 and a tread 50 . Therefore, the outer surface in the tire radial direction X of the support structure 10 is the outer surface in the tire radial direction X of the outer annular portion 30 .

In the following, the thickness of the inner annular portion 20 and the outer annular portion 30 is the dimension along the tire radial direction X. As shown in FIG. The widths of the inner annular portion 20 and the outer annular portion 30 are dimensions along the tire width direction Y shown in FIG.

The inner annular portion 20 is an annular portion along the tire circumferential direction C that constitutes the inner peripheral portion of the non-pneumatic tire 1 . The thickness and width of the inner annular portion 20 are set constant to improve uniformity. A tire wheel (not shown) is arranged in a space on the inner peripheral side of the inner annular portion 20 . The inner peripheral portion of the inner annular portion 20 is fitted and attached to the outer peripheral portion of the rim of the tire wheel. With the inner annulus 20 mounted on the rim, the non-pneumatic tire 1 is mounted on the tire wheel. The inner peripheral surface of the inner annular portion 20 may be provided with a fitting portion configured by a protrusion, a groove, or the like for fitting with the rim.

The inner annular portion 20 can be made of, for example, an elastic resin material, but the material is not limited to resin.

The inner annular portion 20 transmits the rotation of the tire wheel to the spokes 40 and the outer annular portion 30 . The thickness of the inner annular portion 20 is determined from the viewpoint of achieving weight reduction and durability while satisfying the function of sufficiently transmitting the torque to the spokes 40 . Although the thickness of the inner annular portion 20 is not particularly limited, it is preferably 2% or more and 7% or less, and more preferably 3% or more and 6% or less, of the tire cross-sectional height H shown in FIG.

The inner diameter of the inner annular portion 20 is determined according to the dimensions of the rim of the tire wheel on which the non-pneumatic tire 1 is mounted, the application of the vehicle, and the like. For example, when assuming a substitute for a general pneumatic tire, the inner diameter of the inner annular portion 20 may be, for example, 250 mm or more and 500 mm or less, but is not limited to this.

The width of the inner annular portion 20 is appropriately determined according to the application of the vehicle on which the non-pneumatic tire 1 is mounted, the length of the axle, and the like. For example, when assuming a substitute for a general pneumatic tire, the width of the inner annular portion 20 may be 100 mm or more and 300 mm or less, but is not limited to this.

The outer annular portion 30 is an annular portion along the tire circumferential direction C that constitutes the outer peripheral portion of the non-pneumatic tire 1 . The outer annular portion 30 is arranged concentrically with the inner annular portion 20 on the outer peripheral side of the inner annular portion 20 . The thickness and width of the outer annular portion 30 are set constant to improve uniformity.

Outer annular portion 30 transmits the rotation of inner annular portion 20 and spokes 40 to the road surface via tread 50 . The thickness of the outer annular portion 30 is determined from the viewpoint of achieving weight reduction and durability while satisfying the function of sufficiently transmitting the torque from the spokes 40 to the road surface. Although the thickness of the outer annular portion 30 is not particularly limited, it is preferably 2% or more and 7% or less, and more preferably 2% or more and 5% or less, of the tire cross-sectional height H shown in FIG.

The inner diameter of the outer annular portion 30 is appropriately determined according to the dimensions of the rim of the tire wheel on which the non-pneumatic tire 1 is mounted, the application of the vehicle, and the like. For example, when assuming a substitute for a general pneumatic tire, the inner diameter of the outer annular portion 30 may be 420 mm or more and 750 mm or less, but is not limited to this.

The width of the outer annular portion 30 is appropriately determined according to the application of the vehicle on which the non-pneumatic tire 1 is mounted. For example, when assuming a substitute for a general pneumatic tire, the width of the outer annular portion 30 may be 100 mm or more and 300 mm or less, but is not limited to this.

A plurality of spokes 40 connect the inner annular portion 20 and the outer annular portion 30 . The inner annular portion 20 and the outer annular portion 30 connected by a plurality of spokes 40 are arranged concentrically with each other. Each of the plurality of spokes 40 is arranged independently along the tire circumferential direction C. As shown in FIG. As shown in FIG. 1 , when the non-pneumatic tire 1 is in an unloaded state, the plurality of spokes 40 extend linearly in the radial direction substantially parallel to the tire radial direction X when viewed from the side.

As shown in FIGS. 3 and 4 , the plurality of spokes 40 of this embodiment includes a plurality of first spokes 41 and a plurality of second spokes 42 . Neither the first spoke 41 nor the second spoke 42 extends parallel to the tire radial direction X when viewed along the tire circumferential direction C. The first spokes 41 are inclined to one side in the tire axial direction, that is, the tire width direction Y. As shown in FIG. The second spokes 42 are slanted opposite to the first spokes 41 . The first spokes 41 and the second spokes 42 are alternately arranged in the tire circumferential direction C. As shown in FIG.

Specifically, as shown in FIGS. 3 and 4 , the first spokes 41 are arranged from the Y1 side, which is one side of the outer annular portion 30 in the tire width direction Y, to the other side of the inner annular portion 20 in the tire width direction Y. It extends obliquely toward the Y2 side. The second spokes 42 extend obliquely from the Y2 side, which is the other side in the tire width direction Y, of the outer annular portion 30 toward the Y1 side, which is one side of the inner annular portion 20 in the tire width direction Y. .

The inclination angles of the first spoke 41 and the second spoke 42 are the same. Therefore, the first spoke 41 and the second spoke 42 adjacent to each other in the tire circumferential direction C are arranged in a substantially X shape when viewed along the tire circumferential direction C. As shown in FIG. As shown in FIG. 3, the first spokes 41 and the second spokes 42 are inclined at an angle θ with respect to the tire width direction Y, and the angle θ is, for example, 15° or more and 50° or less. is preferred.

As shown in FIG. 3 , each of the first spokes 41 and the second spokes 42 has the same shape symmetrical with respect to the tire equatorial plane E when viewed in the tire circumferential direction C. As shown in FIG. Therefore, hereinafter, the first spokes 41 and the second spokes 42 are collectively referred to as the spokes 40 when there is no need to distinguish between the first spokes 41 and the second spokes 42 and they can be collectively described. .

The spokes 40 are plate-shaped and extend obliquely from the inner annular portion 20 toward the outer annular portion 30 at the angle θ as described above. As shown in FIG. 4 , the spoke 40 has a plate thickness t along the tire circumferential direction smaller than a plate width w, and the direction of the plate thickness t is along the tire circumferential direction C. As shown in FIG. That is, the spokes 40 are formed in a plate shape extending along the plane in the tire radial direction X and the tire width direction Y. As shown in FIG. The plate width w here is the dimension in the direction perpendicular to the direction of inclination in which the spokes 40 extend when the spokes 40 are viewed from the direction along the tire circumferential direction C, as shown in FIG. be. In this embodiment, all the spokes 40 have the same plate thickness t. Moreover, the plate width w of all the spokes 40 is the same.

Since the spokes 40 have a long plate shape, even if the plate thickness t is reduced, the durability of the spokes 40 can be improved by setting the plate width w wide. Furthermore, by reducing the plate thickness t and increasing the number of spokes 40, it is possible to reduce the interval between the spokes 40 adjacent in the tire circumferential direction C while maintaining the rigidity of the non-pneumatic tire 1 as a whole. As a result, the contact pressure caused by the spokes 40 when the tire rolls is dispersed, and the contact pressure can be reduced.

Although the spokes 40 of the present embodiment are parallel to the tire radial direction X when viewed from the side, the spokes 40 are arranged obliquely with respect to the tire radial direction X so as to intersect with the tire radial direction X when viewed from the side. good too.

As shown in FIGS. 3 and 4, the first spokes 41 include a first inner connecting portion 411 connected to the inner annular portion 20 on the Y2 side in the tire width direction, and a first inner connecting portion 411 connected to the Y1 side of the outer annular portion 30 in the tire width direction. and a connecting first outer connection portion 412 . The second spoke 42 includes a second inner connecting portion 421 connected to the inner annular portion 20 on the Y1 side in the tire width direction, and a second outer connecting portion 422 connected to the Y2 side in the tire width direction of the outer annular portion 30. , has Each of the first outer connection portion 412 and the second outer connection portion 422 is an example of a connection portion of the spokes 40 connected to the outer annular portion 30 in this embodiment.

As shown in FIG. 3 , the first inner connecting portion 411 of the first spoke 41 has a shape that widens along the tire width direction Y as it approaches the inner annular portion 20 . A side surface 411a of the first inner connecting portion 411 on the tire width direction Y2 side extends to the end portion 20b of the inner annular portion 20 on the tire width direction Y2 side while gently curving. A side surface 411b on the tire width direction Y1 side of the first inner connection portion 411 extends to the position of the tire equatorial plane E of the inner annular portion 20 while curving toward the tire width direction Y1 side.

The first outer connecting portion 412 of the first spoke 41 has the same shape as the first inner connecting portion 411, and has a shape that widens along the tire width direction as it approaches the outer annular portion 30. . A side surface 412a of the first outer connecting portion 412 on the tire width direction Y1 side extends to the end portion 30a of the outer annular portion 30 on the tire width direction Y1 side while gently curving. A side surface 412b of the first outer connection portion 412 on the tire width direction Y2 side extends to the position of the tire equatorial plane E of the outer annular portion 30 while curving toward the tire width direction Y2 side.

The first inner connection portion 411 is provided in a half region of the inner annular portion 20 on the tire width direction Y2 side. The first outer connection portion 412 is provided in a half region of the outer annular portion 30 on the tire width direction Y1 side.

As shown in FIG. 3 , the second inner connecting portion 421 of the second spoke 42 has a shape that widens along the tire width direction Y as it approaches the inner annular portion 20 . A side surface 421a of the second inner connection portion 421 on the tire width direction Y1 side extends to the end portion 20a of the inner annular portion 20 on the tire width direction Y1 side while being gently curved. A side surface 421b of the second inner connection portion 421 on the tire width direction Y2 side extends to the position of the tire equatorial plane E of the inner annular portion 20 while curving toward the tire width direction Y2 side.

The second outer connecting portion 422 of the second spoke 42 has the same shape as the second inner connecting portion 421, and has a shape that widens in the tire width direction as it approaches the outer annular portion 30. there is A side surface 422a of the second outer connection portion 422 on the tire width direction Y2 side extends to the end portion 30b of the outer annular portion 30 on the tire width direction Y2 side while gently curving. A side surface 422b of the second outer connection portion 422 on the tire width direction Y1 side extends to the position of the tire equatorial plane E of the outer annular portion 30 while curving toward the tire width direction Y1 side.

The second inner connecting portion 421 is provided in a half region of the inner annular portion 20 on the tire width direction Y1 side. The second outer connection portion 422 is provided in a half region of the outer annular portion 30 on the tire width direction Y2 side.

As described above, all the spokes 40 of this embodiment have the same plate thickness t. The dimension of the plate thickness t is not particularly limited. , preferably 1 mm or more and 30 mm or less, more preferably 5 mm or more and 25 mm or less.

As described above, all the spokes 40 of this embodiment have the same plate width w. The plate width w of the spokes 40 is not particularly limited, but in order to sufficiently receive the rotational force from the inner annular portion 20 and the outer annular portion 30 and to allow moderate bending deformation when receiving a load, It is preferably 5 mm or more and 25 mm or less, more preferably 10 mm or more and 20 mm or less. In addition, the plate width w is preferably 110% or more of the plate thickness t, more preferably 115% or more, from the viewpoint of improving the durability and dispersing the contact pressure.

The number of spokes 40 is 80 or more and 300 or less from the viewpoint of enabling weight reduction while sufficiently supporting the load from the vehicle and improving power transmission performance and durability. , and more preferably 100 or more and 200 or less.

The dimension of the spokes 40 in the tire radial direction X may be 26.8 mm or more and 357.5 mm or less, but is not limited to this.

Spokes 40 may be formed from any of the elastic materials listed below. First, as the characteristics of the elastic material, the tensile stress at 10% elongation when a tensile test is performed according to JIS K7312: 1996 from the viewpoint of imparting appropriate rigidity while ensuring sufficient durability. is preferably 50 MPa or more and 120 MPa or less, more preferably 70 MPa or more and 105 MPa or less.

If the Young's modulus of the spokes 40 is less than 50 MPa, sufficient rigidity may not be obtained, and the spokes 40 adjacent in the tire circumferential direction C may come into contact with each other. On the other hand, when the Young's modulus of the spokes 40 exceeds 120 MPa, the rigidity becomes excessively high, degrading the ride comfort.

Examples of the elastic material used as the base material of the spokes 40 include thermoplastic elastomers, crosslinked rubbers, and other resins.

Examples of thermoplastic elastomers include polyester elastomers, polyolefin elastomers, polyamide elastomers, polystyrene elastomers, polyvinyl chloride elastomers, polyurethane elastomers, and the like.

Either natural rubber or synthetic rubber can be used as the rubber material constituting the crosslinked rubber. Synthetic rubbers include styrene butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IIR), nitrile rubber (NBR), hydrogenated nitrile rubber (hydrogenated NBR), chloroprene rubber (CR), ethylene propylene rubber ( EPDM), fluorine rubber, silicone rubber, acrylic rubber, urethane rubber, and the like. These rubber materials may be used in combination of two or more as needed.

Other resins include thermoplastic resins and thermosetting resins. Examples of thermoplastic resins include polyethylene resins, polystyrene resins, and polyvinyl chloride resins. Thermosetting resins include epoxy resins, phenol resins, polyurethane resins, silicone resins, polyimide resins, melamine resins, and the like.

Among the above elastic materials, urethane resin is preferably used for the spokes 40 from the viewpoint of moldability, workability and cost. A foam material can also be used as the elastic material. That is, foamed thermoplastic elastomers, crosslinked rubbers, and other resins can be used.

The elastic material used as the base material of the spokes 40 may be reinforced with reinforcing fibers. Examples of reinforcing fibers include long fibers, short fibers, woven fabrics, non-woven fabrics, and the like. Reinforcing fibers include rayon cords, polyamide cords such as nylon-6,6, polyester cords such as polyethylene terephthalate, aramid cords, glass fiber cords, carbon fibers, and steel cords.

Reinforcement of the elastic material is not limited to reinforcement with reinforcing fibers. For example, reinforcement by the addition of particulate fillers may be provided. Granular fillers to be added include carbon black, silica, ceramics such as alumina, fillers of other inorganic materials, and the like.

By the way, the inner annular portion 20 and the outer annular portion 30 described above are preferably formed of the same resin material as the spokes 40. In that case, for example, the inner annular portion 20 and the outer annular portion 20 are formed by cast molding. 30 and spokes 40 can be integrally molded.

The tread 50 is provided on the outer peripheral surface of the outer annular portion 30 and constitutes the outermost peripheral portion of the non-pneumatic tire 1 . The tread 50 is formed by vulcanizing and bonding the support structure 10 and the tread rubber composition 3, as described above. The tread 50 has a tread surface 51 that contacts the road surface on its outer peripheral surface. A tread 51 of the tread 50 is provided with a tread pattern formed of a plurality of grooves and land portions in the same manner as a conventional pneumatic tire.

Note that the tread 50 may have a structure in which a plurality of vulcanized rubber layers having different components and properties are laminated (for example, two layers or three layers).

Moreover, the non-pneumatic tire 1 of the present embodiment may further include a reinforcing layer (not shown). The reinforcing layer may be embedded in the outer annular portion 30 . Alternatively, a reinforcing layer may be provided between the outer annular portion 30 and the tread 50 . The reinforcing layer is a cylindrical layer extending along the tire circumferential direction C. As shown in FIG.

The reinforcing layer is evenly arranged over the entire circumference of the tire in order to suppress the occurrence of buckling in which the outer annular portion 30 is bent in the tire radial direction X at the center portion in the tire width direction Y. The reinforcing layer is configured by, for example, steel cords arranged substantially parallel to the tire width direction Y. As shown in FIG. A cylindrical metal ring, a high modulus resin ring, or the like may be used as the reinforcing layer. For example, as the reinforcing layer, a ring made of fiber reinforced plastic (FRP) such as carbon fiber reinforced plastic (CFRP) or glass fiber reinforced plastic (GFRP) may be used.

By providing the reinforcing layer, the rigidity of the non-pneumatic tire 1 is ensured, and the ground contact of the tread 50 to the road surface is improved.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and the above embodiments may be changed as appropriate within the scope of the present invention.

Examples of the present invention will be described below, but the present invention is not limited to the examples. Since it is difficult to directly measure the adhesion between the support structure and the tread rubber using a non-pneumatic tire, a test piece simulating a non-pneumatic tire was used to measure the adhesion.

[Example 1]
A urethane resin sheet having a width of 100 mm, a length of 200 mm, and a thickness of 2.0 mm was coated with a sanding belt having a particle size of #80 and a belt sander from one end of a urethane resin sheet with a length of 100 mm. A buffing process was carried out so as to obtain a thickness of 0.2 μm. Next, after air blowing the bonding area, it was degreased and washed with ethanol. Next, using a low-frequency corona treatment device Multidyne (manufactured by Navitas Machinery), the adhesion area was corona-treated at a treatment speed of 4.8 m/min. A vulcanized adhesive containing a halogenated polymer and a metal oxide (acid acceptor) was then applied to the adhesive area using a brush and then dried at 80° C. for 10 minutes. Chemlok (registered trademark) 6108S (manufactured by LOAD) (vulcanized adhesive A) and Metalloc PH-50 (manufactured by Toyo Kagaku Kenkyusho) (vulcanized adhesive B) were used as vulcanizing adhesives. Next, after the unvulcanized rubber composition was adhered to the adhesion region, vulcanization adhesion was performed under the conditions of a pressure of 1 MPa, a heating temperature of 140° C., and a heating and pressing time of 36 minutes. Next, it was cut into a width of 25 mm and a length of 150 mm to obtain a test piece.

[Example 2]
A 100 mm long adhesive area from one end of the urethane resin sheet is treated with plasma at a treatment speed of 3.6 m/min using a surface treatment apparatus Plasmadyne (manufactured by Navitas Machinery) instead of corona treatment of the adhesive area. A test piece was obtained in the same manner as in Example 1, except that

[Example 3]
A 100 mm long adhesive area from one end of the urethane resin sheet was treated with a surface modification device, Air Plasma (manufactured by Kasuga Denki Co., Ltd.), instead of performing corona treatment on the adhesive area. A test piece was obtained in the same manner as in Example 1, except that it was treated.

[Comparative Example 1]
A test piece was obtained in the same manner as in Example 1, except that the adhesive area was not corona treated.

[Arithmetic mean roughness Ra of adhesive region]
The arithmetic mean roughness Ra of the adhesion region was measured using a contact-type surface roughness meter.

[Wetting Tension of Adhesive Area]
The wetting tension of the corona-treated or plasma-treated adhesive areas was measured according to JIS K6768:1999.

[T-type peel test]
With reference to JIS K6854-3:1999, a T-type peel test was performed at room temperature to measure the average peel strength of the test piece.

Table 1 shows the test piece preparation conditions and the measurement results of the average peel strength.

From Table 1, it can be seen that the test pieces of Examples 1 to 3 have high average peel strength regardless of whether vulcanized adhesive A or B is used. On the other hand, in the test piece of Comparative Example 1, since the surface of the urethane resin sheet was not modified, the average peel strength was low regardless of whether the vulcanized adhesive A or B was used.

REFERENCE SIGNS LIST 1 non-pneumatic tire 1A precursor of non-pneumatic tire 2 vulcanizing adhesive 3 rubber composition for tread 10 support structure 20 inner annulus 20a, 20b end 30 outer annulus 30a, 30b end 40 spoke 41 first Spoke 42 Second spoke 411 First inner connection portion 411a, 411b Side surface 412 First outer connection portion 412a, 412b Side surface 421 Second inner connection portion 421a, 421b Side surface 422 Second outer connection portion 422a, 422b Side surface 50 tread 51 tread surface 60 vulcanizer 61 lower die 62 upper die 63, 64 segments 63a, 64a molding surface 65, 66 packing C tire circumferential direction E tire equatorial plane O axial center X tire radial direction Y tire width direction

Claims (3)

A method for manufacturing a non-pneumatic tire comprising a support structure containing a resin and a tread positioned radially outwardly of the support structure and extending along the tire circumferential direction, the method comprising:
a step of surface-modifying the outer surface of the support structure in the tire radial direction so that the wet tension is 40 mN/m or more and 60 mN/m or less;
applying a vulcanizing adhesive to the surface-modified surface of the support structure;
A method for manufacturing a non-pneumatic tire, comprising a step of vulcanizing and bonding a support structure coated with the vulcanizing adhesive and a tread rubber composition. The method for manufacturing a non-pneumatic tire according to claim 1, wherein the surface modification is surface modification by corona treatment or plasma treatment. The resin is a urethane resin,
3. A method for manufacturing a non-pneumatic tire according to claim 1 or 2, wherein the vulcanizing adhesive comprises a halogenated polymer.

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